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Your search keyword '"Venters, Tonia M."' showing total 4 results
Start Over Author "Venters, Tonia M." Topic dark matter
4 results on '"Venters, Tonia M."'

1. The Snowmass UHECR White Paper on Ultra-High-Energy Cosmic Rays.

Author

Schroeder, Frank G., Coleman, Alan, Eser, Johannes, Mayotte, Eric, Sarazin, Fred, Soldin, Dennis, and Venters, Tonia M.

Subjects
DARK matter, COSMIC rays, TELESCOPES, ASTROPHYSICS, PARTICLE physics
Abstract

This proceeding summarizes the talk given at the opening of the UHECR 2022 conference in L'Aquila on the whitepaper 'Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers' [Astroparticle Physics 149 (2023) 102819 - arXiv:2205.05845] that has been prepared for the Snowmass survey in the USA. The whitepaper provides an overview of recent progress and open questions regarding the particle physics and astrophysics related to ultra-high-energy cosmic rays (UHECR) and outlines the connections between the particle and astrophysics aspects of cosmic rays. It also discusses what instrumentation is needed to address the major scientific questions in ultra-high-energy cosmic-ray physics. While the upgraded Pierre Auger Observatory and Telescope Array will remain the workhorses at the highest energies in the current decade, new experiments with significantly higher exposure are needed in the coming decade. Ground arrays featuring simultaneous detection of the position of the shower maximum and the size of the muonic component will enable particle astronomy by measuring the rigidity of individual events. They should be complemented by other detectors maximizing the total exposure. This can be achieved by a few next-generation experiments using the latest developments in detection and analysis techniques: GRAND as a ground-based radio array, and POEMMA as a space-borne stereo fluorescence telescope will feature complementary approaches to provide maximum exposure; IceCube-Gen2 with its surface array, and GCOS aim at increased statistics with high accuracy for particle physics and rigidity-based galactic and extra-galactic astrophysics. While designed to discover the astrophysical cosmic-ray sources at the highest energies, the same experiments also contribute to particle physics, e.g., by studying the muon puzzle in cosmic-ray air showers, and by their discovery potential for exciting new physics, such as certain Dark Matter candidates. With the full whitepaper available as a reference, this proceeding will briefly present the science cases of the experiments, highlighting their individual strengths and outlining how they complement each other. [ABSTRACT FROM AUTHOR]

Published
2023
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2. COMPONENTS OF THE EXTRAGALACTIC GAMMA-RAY BACKGROUND.

Author

STECKER, FLOYD W. and VENTERS, TONIA M.

Subjects
*GALAXY formation, *OPEN clusters of stars, *GAMMA ray astronomy, *DARK matter, *ANNIHILATION reactions
Abstract

We present new theoretical estimates of the relative contributions of unresolved blazars and star-forming galaxies to the extragalactic γ-ray background (EGB) and discuss constraints on the contributions from alternative mechanisms such as dark matter annihilation and truly diffuse γ-ray production. We find that the Fermi source count data do not rule out a scenario in which the EGB is dominated by emission from unresolved blazars, though unresolved star-forming galaxies may also contribute significantly to the background, within order-of-magnitude uncertainties. In addition, we find that the spectrum of the unresolved star-forming galaxy contribution cannot explain the EGB spectrum found by EGRET at energies between 50 and 200 MeV, whereas the spectrum of unresolved flat spectrum radio quasars, when accounting for the energy-dependent effects of source confusion, could be consistent with the combined spectrum of the low-energy EGRET EGB measurements and the Fermi-Large Area Telescope EGB measurements. [ABSTRACT FROM AUTHOR]

Published
2011
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3. Hunting super-heavy dark matter with ultra-high energy photons.

Author

Anchordoqui, Luis A., Bérat, Corinne, Bertaina, Mario E., Castellina, Antonella, Deligny, Olivier, Engel, Ralph, Farrar, Glennys R., Ghia, Piera L., Hooper, Dan, Kalashev, Oleg, Kuznetsov, Mikhail, Niechciol, Marcus, Olinto, Angela V., Papenbreer, Philipp, Perrone, Lorenzo, Rautenberg, Julian, Romero-Wolf, Andrés, Savina, Pierpaolo, Soriano, Jorge F., and Venters, Tonia M.

Subjects
*ULTRA-high energy cosmic rays, *DARK matter, *PARTICLE acceleration, *PHOTONS, *PARTICLE physics, *COLD fusion
Abstract

At any epoch, particle physics must be open to completely unexpected discoveries, and that is reason enough to extend the reach of searches for ultra-high energy (UHE) photons. The observation of a population of photons with energies E ≳ 100 EeV would for example imply the existence of either a completely new physical phenomena, or particle acceleration mechanisms heretofore never seen or imagined. But as we outline in this Letter of Interest, there are also good arguments for super-heavy dark matter (SHDM) in a parameter range such that it could be discovered via its decays to, in particular, UHE photons. Only ultra-high energy cosmic ray observatories have capabilities to detect UHE photons. We first investigate how current and future observations can probe and constrain SHDM models in important directions, and then outline some of the scenarios that motivate such searches. We also discuss connections between constraints on SHDM and on the parameter values of cosmological models. [ABSTRACT FROM AUTHOR]

Published
2021
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4. Indirect dark matter searches at ultrahigh energy neutrino detectors.

Author

Guépin, Claire, Aloisio, Roberto, Cummings, Austin, Anchordoqui, Luis A., Krizmanic, John F., Olinto, Angela V., Reno, Mary Hall, and Venters, Tonia M.

Subjects
*NEUTRINO detectors, *NEUTRINOS, *DARK matter, *PROPERTIES of matter, *GALACTIC halos, *CHERENKOV counters, *ANNIHILATION reactions
Abstract

High to ultrahigh energy neutrino detectors can uniquely probe the properties of dark matter χ by searching for the secondary neutrinos produced through annihilation and/or decay processes. We evaluate the sensitivities to dark matter thermally averaged annihilation cross section ⟨σv⟩ and partial decay width Γχ → νν (in the mass scale 107 ≤ mχ/GeV ≤ 1015) for next generation observatories like POEMMA (Probe of Extreme Multi-Messenger Astrophysics) and GRAND (Giant Radio Array for Neutrino Detection). We show that in the range 107 ≤ mχ/GeV ≤ 1011, space-based Cherenkov detectors like POEMMA have the advantage of full-sky coverage and rapid slewing, enabling an optimized dark matter observation strategy focusing on the Galactic Center. We also show that ground-based radio detectors such as GRAND can achieve high sensitivities and high duty cycles in radio quiet areas. We compare the sensitivities of next generation neutrino experiments with existing constraints from IceCube and updated 90% C.L. upper limits on ⟨σv⟩ and Γχ → νν using results from the Pierre Auger Collaboration and Antarctic Impulsive Transient Antenna. We show that in the range 107 ≤ mχ/GeV ≤ 1011, POEMMA and GRAND10k will improve the neutrino sensitivity to particle dark matter by factors of 2 to 10 over existing limits, whereas GRAND200k will improve this sensitivity by 2 orders of magnitude. In the range 1011 ≤ mχ/GeV ≤ 1015, POEMMA's fluorescence observation mode will achieve an unprecedented sensitivity to dark matter properties. Finally, we highlight the importance of the uncertainties related to the dark matter distribution in the galactic halo, using the latest fit and estimates of the galactic parameters. [ABSTRACT FROM AUTHOR]

Published
2021
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